I've created a shopify app which adds a new theme section to active theme when it is installed. Now I am concerned that if the shopify store user changed their store's theme then my theme section changes will get removed.
Is there a way to persist my theme section changes. If not, can I listen to an event/webhook from shopify which will inform me of the change in theme?
There are webhooks for themes/update and themes/publish. You might try monitoring for publish events with theme_id or name properties that don't match your expected theme and issue warning notifications about those section data going away.
This is an example response from the docs:
{
"id": null,
"name": "Comfort",
"created_at": "2021-04-01T14:58:14-04:00",
"updated_at": "2021-04-01T14:58:14-04:00",
"role": "main",
"theme_store_id": 1234,
"previewable": true,
"processing": false
}